The present invention generally relates to particulate filtration screen apparatus and, in a preferred embodiment thereof, more particularly relates to weld joint strength test apparatuses and methods for use in conjunction with welded metal screen structures such as, for example, sand control screen structures employed in various downhole assemblies used in the water well, environmental, industrial filtration, and oil and gas industries.
Tubular filter structures of the type, for example, having a perforated tubular core surrounded by a welded metal filter screen structure that acts as a pre-filter for removing particulate matter from fluid entering the core through its side wall perforations are used in a variety of applications including but not limited to downhole oil and gas recovery operations, water wells, and industrial pollutant filtration in manufacturing operations. Typically, the metal screen structure comprises a circumferentially spaced series of parallel metal rods outwardly overlying the tubular perforated filter core and longitudinally extending parallel to its axis, and a longitudinally spiraled helical metal wire wrap outwardly circumscribing the rods, with the helical wire wrap being welded each rod at its junctures therewith.
For both quality control and operating strength verification purposes it is desirable to be able to test the tensile breaking force of representative rod/wrap weld joints in a batch of tubular filter structures. Various types of tensile testing devices are potentially available for determining the tensile breaking force of selected individual rod/wrap member weld joints. However, as is well known, these machines tend to be relatively expensive.
Moreover, due to the tubular configuration of the screen structure to be tested, it is difficult to prepare a suitable test specimen from the screen structure for use in the machine, and it is also quite difficult to operatively mount the prepared specimen in the machine. Additionally, in preparing the specimen, the individual weld joint to be tested can easily be damaged, typically leading to erroneous (i.e., lowered) weld joint strength test readings.
In view of the foregoing, it can be readily seen that it would be desirable to provide an improved metal filtration screen weld joint test apparatus and methods that eliminate or at least substantially reduce the problems, limitations and disadvantages typically associated with the use of conventional tensile testing apparatuses as generally described above. It is accordingly an object of the present invention to provide an improved test apparatus and methods.